The least-squares goodness-of-fit parameter S for all data
after the final cycle of refinement. Ideally, account should be
taken of parameters restrained in the least-squares refinement.
See also the definition of _refine.ls_restrained_S_all.
( sum|w |Yobs - Ycalc|2| )1/2
S = ( ---------------------------- )
( Nref - Nparam )
Yobs = the observed coefficients
(see _refine.ls_structure_factor_coef)
Ycalc = the calculated coefficients
(see _refine.ls_structure_factor_coef)
w = the least-squares reflection weight
[1/(e.s.d. squared)]
Nref = the number of reflections used in the refinement
Nparam = the number of refined parameters
sum is taken over the specified reflections